example custom sensor

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensorComponentCustom3D.cs

+using UnityEngine;
+using UnityEngine.Serialization;
+
+namespace Unity.MLAgents.Sensors
+{
+    public class CustomRayPerceptionOutput : RayPerceptionOutput
+    {
+        public CustomRayPerceptionOutput()
+        {
+            CustomObservationSizePerRay = 3;
+        }
+
+        public override void GetCustomObservationData(RayOutput rayOutput, float[] buffer)
+        {
+            var rb = rayOutput.HitGameObject.GetComponent<Rigidbody>();
+            if (rb != null)
+            {
+                buffer[0] = rb.velocity.x;
+                buffer[1] = rb.velocity.z;
+                buffer[2] = rb.mass;
+            }
+        }
+    }
+
+    /// <summary>
+    /// A component for Custom 3D Ray Perception.
+    /// </summary>
+    [AddComponentMenu("ML Agents/Custom Ray Perception Sensor 3D", (int)MenuGroup.Sensors)]
+    public class RayPerceptionSensorComponentCustom3D : RayPerceptionSensorComponent3D
+    {
+        public override ISensor[] CreateSensors()
+        {
+            var rayPerceptionInput = GetRayPerceptionInput();
+            var rayPerceptionOutput = new CustomRayPerceptionOutput();
+
+            m_RaySensor = new RayPerceptionSensor(SensorName, rayPerceptionInput, rayPerceptionOutput);
+
+            if (ObservationStacks != 1)
+            {
+                var stackingSensor = new StackingSensor(m_RaySensor, ObservationStacks);
+                return new ISensor[] { stackingSensor };
+            }
+
+            return new ISensor[] { m_RaySensor };
+        }
+    }
+}

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensorComponentCustom3D.cs.meta

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